One of the great challenges of the 21st Century is increasing life expectancy, while at the same time maintaining quality of life in an aging population. Regenerative medicine is, therefore, a new strategy that seeks to repair damaged or diseased tissues to their original state or function. For example, regenerative medicine seeks to help natural healing processes to work faster by using special materials with human cell cultures, often referred to as “scaffolds” or “bioscaffolds,” which act as three-dimensional templates for cell growth and differentiation and formation of living tissues.
Synthetic scaffolds have been proposed as a new means of tissue reconstruction and repair. Scaffolds belong to a new generation of biomedical structures, which rely on the concept of regeneration of diseased or damaged tissue to its original state or function. In contrast, current clinical methods are based on replacement by implantation or transplantation. Current clinical methods such as implantation or transplantation possess well-known drawbacks. Those drawbacks include, for example, lack of ability to self-repair, limited vascularization of implants, limited number of donors, and possibility of rejection of transplanted tissues.
Scaffolds serve as both a physical support and as an adhesive substrate for isolated cells, during in vitro culturing and subsequent in vivo implantation. Scaffolds may be used to deliver cells to desired sites in the body, to define a potential space for engineered tissue, and/or to guide the process of tissue development. Cell transplantation on scaffolds has been explored for the regeneration of skin, nerve, liver, and pancreas tissues using various biological and synthetic materials. In particular, scaffolds containing dual porosity at the nanoscale and macroscale have been alleged to exhibit better performance in terms of crystallization of hydroxycarbonate apatite, cell adhesion and proliferation, and vascularization. Known materials, however, lack sufficient mechanical strength to be of practical use or lack an interconnected pore morphology that is compatible with vascularization.
Accordingly, a continuing and unmet need exists for new and improved synthetic bioactive tissue scaffolds, scaffold materials, as well as for methods for fabricating scaffolds having interconnected multi-modal porosity. A further need exists for bioactive and biocompatible glass systems (such as soda-lime phosphosilicates), including glasses having morphology and textures that enable formation of a bonelike hydroxyapatite layer.